This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The goal of the proposed subproject is to establish Raman spectroscopy as a viable clinical tool for in vivo measurement of blood glucose, based on our previous successful application in tissue phantoms and animal models. However, the spectral signals emanating from biological tissue are often weak, and therefore efficient collection is essential. Only approximately 1010 of the incident light is Raman scattered, severely limiting data-acquisition rates. The excitation light power that can be delivered to a given area of tissue is limited by undesirable effects such as overheating. It is therefore important to maximize the light collected. While we were able to significantly enhance light collection efficiency in a bench-top system using an off-axis gold coated paraboloidal mirror, the footprint requirements of the clinical instrument necessitate the use of a fiber optic-based excitation and collection device. To accomplish this, we have designed a compact spectroscopic system, that incorporates a tunable laser and a broadband source (which are critical for fluorescence removal and turbidity correction, respectively), alongside a flexible fiber probe capped with a compound parabolic concentrator (CPC).